Nord-Lock Type Wedge Locking Washers Stops screws from vibrating loose. Special construction is actually 2 washers in one. The Cams and Serrations act together to form a tension that is very effective in fighting vibration! A million uses...great to have on-hand in the workshop.
These two-piece washers create a wedge by locking into each other to prevent rotation in high-vibration and dynamic load environments; such as in airplanes, jets and helicopters. Wedge-Lock washers have a higher clamp load than serrated lock washers
and their locking function is not affected by lubrication. Teeth on one half of the washer engage with wedges on the other when tightened, utilizing tension instead of friction to secure your screw or bolt.
M3 also fits #4 Screws and 4-40 Bolts,
M4 also fits #6 and #8 Screws and 6-32 and 8-32 Bolts
M5 also fits #10 Screws and 10-32 Bolts
M6 also fits 1/4" Screws and 1/4-20 Bolts